In general, a cutting tool includes a holder made of steel and a cutting insert made of cemented carbide steel and the cutting insert is indexably mounted to the holder through a clamp screw.
Such an indexable cutting tool is advantageous in that the cutting insert thereof can be replaced with a new one if a cutting edge of the cutting insert is worn out. However, when coupling between the cutting insert and the holder is defective, problems such as separation of the cutting insert and damage of the clamp screw may occur.
In the mean time, the cutting insert is mounted to a tool body, with a back cross-section thereof being perpendicular to a rotational axis thereof. In this structure, a longitudinal resistance can be supported stably, but a reaction force with respect to a lateral cutting resistance is offset only by a clamping force of the clamp screw which fixes the cutting insert to the tool body.
During processing of a work-piece in a high-feed condition, a large cutting resistance acts in a cutting edge of the cutting insert and thus a sufficient clamping force for the cutting resistance cannot be provided merely by the clamp screw. In this condition, the clamp screw may be damaged.
The present invention is conceived to solve the aforementioned problems, an object of the present invention is to provide a cutting insert and a cutting tool comprising the same, in which a back side face portion of the cutting insert is formed in a non-symmetrical convex “V” shape for dispersion of a force applied to a clamp screw, thereby preventing damage of the clamp screw and firmly clamping the cutting insert to a holder.
In addition, another object of the present invention is to provide a cutting insert and a cutting tool comprising the same, in which the cutting insert is capable of reducing manufacturing tolerance by providing easiness in manufacturing and has superior mounting precision.
According to an aspect of the present invention for achieving the objects, there is provided a cutting tool, which comprises an upper face and a lower face; a front side face portion and a back side face portion, the front and back side face portions connecting the upper face and the lower face; and a through-hole passing through the upper face and the lower face, wherein a cutting edge is formed in the front side face portion, and the back side face portion is provided with a first inclined face and a second inclined face which are inclined forwardly at different angles, respectively, with respect to a plane normal to a rotational axis, and the first inclined face is longer than the second inclined face so that the back side face portion has a non-symmetrical convex “V” shape.
According to another aspect of the present invention for achieving the objects, there is provided a cutting tool, which comprises a holder having a pocket formed on a front end portion thereof, the pocket having a pair of jaws; and a cutting insert indexably mounted to the pocket, wherein the cutting insert comprises a upper face and a lower face corresponding to each of jaws, respectively, a front side face portion and a back side face portion corresponding to the pocket of the holder, the front and back side face portions connecting the upper face and the lower face, and a through-hole passing through the upper face and the lower face, a cutting edge is formed in the front side face portion, the back side face portion is provided with a first inclined face and a second inclined face which are inclined forwardly at different angles, respectively, with respect to a plane normal to a rotational axis, and the first inclined face is longer than the second inclined face so that the back side face portion has a non-symmetrical convex “V” shape.
As described above, the cutting insert and the cutting tool comprising the same according to the present invention provide a stable supporting structure with respect to an axial direction, and prevent damage of the clamp screw and firmly clamp the cutting insert to the holder by dispersing a force applied to the clamp screw.
In addition, the cutting insert and the cutting tool comprising the same according to the present invention are easy to manufacture due to a large manufacturing tolerance and have superior mounting precision.